Optical Imaging Apparatus for Diagnosis and Image Processing Method

1. An optical imaging apparatus for diagnosis which obtains reflection light from biological tissue of a body lumen by moving a transmission and reception unit, that carries out optical transmission and reception, continuously in an axial direction while rotating the unit in a circumferential direction inside the body lumen, and which constructs a tomographic image of the biological tissue using line data of interference light obtained by making the obtained reflection light and a reference light interfere with each other, the optical imaging apparatus comprising: first analysis means for reading-out line data used for construction of a predetermined tomographic image and for analyzing intensity change in transmission direction of the light from the transmission and reception unit for every one of the respective line data; first detection means for detecting, based on the analysis result by the first analysis means, pixel data expressing stent position in the transmission direction for every one of the respective line data when the analysis result includes the intensity change exceeding a predetermined threshold value, wherein each pixel data expressing the stent position includes respective positional information in the transmission direction; first labeling means for labeling each pixel data expressing the stent position detected for every one of the respective line data based on the respective positional information of the pixel data expressing the stent position, the first labeling means comparing the positional information of one pixel data expressing the stent position with the positional information of other pixel data expressing the stent position in adjacent line data in the circumferential direction and applying, if the positional information of the one pixel data expressing the stent position is within a predetermined range consistent with the positional information of the other pixel data expressing the stent position in adjacent line data in the circumferential direction, a same label to the one pixel data expressing the stent position and the other pixel data expressing the stent position, wherein labeling groups are defined as groups of pixel data applied with the same labels by the first labeling means; first elimination means for eliminating labeling groups in which the number of pixel data in one labeling group is a predetermined value or less; first calculation means for calculating, for each labeling group which was not eliminated by the first elimination means, a center position of the labeling group based on the positional information of each pixel data of the labeling group; and first generation means for generating a stent closed-curve using the center position in each labeling group, which was calculated by the first calculation means.

2. The optical imaging apparatus for diagnosis according to claim 1 , further comprising: second analysis means for reading-out line data used for constructing a predetermined tomographic image and for analyzing maximum intensity in the transmission direction of light from the transmission and reception unit for every one of the respective line data; second detection means for detecting pixel data expressing inner-wall position of the biological tissue in the transmission direction for every one of the respective line data based on the analysis result by the second analysis means, wherein each pixel data expressing the inner-wall position includes respective positional data in the transmission direction; second labeling means for labeling each pixel data expressing the inner-wall position detected for every one of the respective line data based on the respective positional information of the pixel data expressing the inner-wall position, the second labeling means comparing the positional information of one pixel data expressing the inner-wall position with the positional information of other pixel data expressing the inner-wall position in adjacent line data in the circumferential direction and applying, if the positional information of the one pixel data expressing the inner-wall position is within a predetermined range consistent with the positional information of the other pixel data expressing the inner-wall position in adjacent line data in the circumferential direction, a same label to the one pixel data expressing the inner-wall position and the other pixel data expressing the inner-wall position, wherein second labeling groups are defined as groups of pixel data applied with the same labels by the second labeling means; second elimination means for eliminating second labeling groups in which the fluctuation of respective positional information of pixel data, included in one second labeling group is larger than a predetermined value; second calculation means for calculating, for each second labeling group which was not eliminated by the second elimination means, a center position of the second labeling group based on the positional information of each pixel data of the second labeling group; and second generation means for generating a closed-curve of the inner wall by using the center position of each second labeling group, which was calculated by the second calculation means.

3. An image processing method of an optical imaging apparatus for diagnosis which obtains reflection light from biological tissue of a body lumen by moving a transmission and reception unit, that carries out optical transmission and reception, continuously in an axial direction while rotating the unit in a circumferential direction inside the body lumen, and which constructs a tomographic image of the biological tissue using line data of interference light obtained by making the obtained reflection light and a reference light interfere with each other, the method comprising: reading-out line data used for construction of a predetermined tomographic image and analyzing intensity change in transmission direction of the light from the transmission and reception unit for every one of the respective line data; detecting, based on the analyzing of the intensity change, pixel data expressing stent position in the transmission direction for every one of the respective line data when a result of the analyzing includes the intensity change exceeding a predetermined threshold value, wherein each pixel data expressing the stent position includes respective positional information in the transmission direction; labeling each pixel data expressing the stent position detected for every one of the respective line data based on the respective positional information of the pixel data expressing the stent position by comparing the positional information of one pixel data expressing the stent position with the positional information of other pixel data expressing the stent position in adjacent line data in the circumferential direction and applying, if the positional information of the one pixel data expressing the stent position is within a predetermined range consistent with the positional information of the other pixel data expressing the stent position in adjacent line data in the circumferential direction, a same label to the one pixel data expressing the stent position and the other pixel data expressing the stent position, wherein labeling groups are defined as groups of pixel data applied with the same labels; eliminating labeling groups in which the number of pixel data in one labeling group is a predetermined value or less; calculating, for each labeling group which was not eliminated in the elimination process, a center position of the labeling group based on the positional information of each pixel data of the labeling group; and generating a stent closed-curve using the center position in each labeling group, which was calculated in the calculation process.